<!DOCTYPE html>
<html>
    <head lang="en">
    <meta charset="UTF-8">
    </head>
    <body>
        <script>
        function cloneContent(){
            var div = document.getElementById("div");
            var rangeObj =document.createRange();
            rangeObj.selectNodeContents(div);
            var docFrangMent = rangeObj.cloneContents();
            div.appendChild(docFrangMent); 
        }

        </script>
        <div id="div">
            你好么
            <br/>
            <button onclick="cloneContent()">克隆</button>
            <br/>
        </div>
    </body>

</html>